Try-fourciiambault



UNiTnn STATES CHARLES EDOU'ARD GUILLAUME, OF SEVRES, AIEIDIOUIS CHARLES DUMAS, OF PARIS, FRANCE, ASSIGNORS TO THE SOCIETE ANONYME DE COMMEN- TRY-FOURCHAMBAULT, OF PARIS, FRANCE.

MANUFACTURE OF ALLOYS.

SPECIFICATION forming part of Letters Patent No. 626,609, dated {lune 6, 1899.

Application filed November 16, 1897. Serial No. 658,741. (Specimensd ject-matter of Letters Patent in France, No. 1

262,737, dated December 31, 1896,) of which the following is a specification.

This invention relates to alloys, and especially to alloys containing iron and nickel, and aims to provide an improved alloy which shall be non-expansible, and improvements whereby a predetermined degree of expansibility can be obtained by combining with such alloy other metals or alloys, and provides an improved process for the manufacture of alloys.

\Ve have discovered that alloys of iron and nickel expand or contract under variations of heat in accordance with laws which are peculiar to such alloys and which are generally very diiferent from the laws governing the expansion and contraction ofiron or nickel separately.

We have found from numerous experiments that by varying the proportions of nickel and iron in the alloy products are obtained whose coefficients of expansion vary within considerable limits. When the proportion of nickel is less than about twenty per cent, the coefficient of expansion lies between that of iron and that of nickel; but this coefficient of expansion increases when the proportion of nickel is raised until with twenty-two to twenty-four per cent. of nickel it closely approximates that of brass, when it attains its maximum. The coefficient of expansion then progressively diminishes with thus varies between a maximum and a minimum, the minimum being approximately zero and this minimum expansion being attained by alloying about thirty-seven per cent. of nickel with the iron. It is this practically non-expansible' alloy obtained by alloying nickel and iron in the proportions specified which forms the subject of the present invention.

An alloy having any desired coefficient of expansion between the maximum and minimum may be obtained by introducing the corresponding quantity of nickel, either more or less than thirtyseven per cent, (which gives the minimum of expansibility.) Thus to obtain an alloy having the same coefficient of expansion as glass (which is slightly less than that of platinum) the proportion of nickel maybe either twenty-nine per cent. or fortyfour per cent.

The improved alloy may be produced in crucibles or Martin furnaces by any of the ordinary processes employed in the steel manufacture The alloys produced in accordance with this invention may contain, besides iron and nickel, varying quantities of the metals and lnetalloids which ordinarily enter into the composition of steel, as carbon, silicon, and manganese, or, as impurities, traces of sulfur or of phosphorus. The addition of small quantities of chromium or tu ngsten does not noticeably affect the expansibility of our alloy.

The improved non-expansible alloy is particularly adapted for the construction of standard and geodetic rules, level-rulers, and all astronomical instruments, and in general for all exact instruments or tools for which it is desirable to avoid deformation. It will also be of great service in the construction of compensating penduluins and balances where it is desirable to maintain constant the distance between the point of suspension and the center of oscillation of the instrument. The alloy may also be employed with advantage for invariable springs for clockwork movements.

By employing this improved alloy for the tubes of steam-boilers or other apparatus or parts of apparatus exposed to a greater heat than other parts the deterioration and excessive tension which result from too great expansion are avoided. Conversely, by making certain elements of apparatus of non expansible alloy systematic tension or deformation may be produced which are much stronger than have been hitherto possible. As examples, there may be mentioned bimetallic thermometers, the expansion-plates of thermal variation galvanoineters, fire-alarms, and compensators.

It will be understood that the non-expansible alloy may be mixed in suitable proportion with other metals or alloys for the production of alloys having the same expansion as other substances with which they are combined or connected--such as glass, crystal, &c.-and this will be of particular advantage for the manufacture of incandescent lamps, Crookes tubes and the like, spectacle-frames,

- mirrors, and optical instruments in general.

metal or alloy of known expansibility, whereby a product of predetermined expansibility is obtained, substantially as described.

In witness whereof we have hereunto signed our names in the presence of two subscribing witnesses.

CHARLES EDOUARD GUILLAUME. LOUIS CHARLES DUMAS. W'itnesses JULEs ARMENGAUD, J eune, PAUL F. PAQUES. 

